Not all router work right with the 360 wireless. I've had many routers from many companies and the only one that works with all my systems and computers without a lot of problems is *choke* Linksys. If you get one, keep in mind they a shit for Techs and will try their best to keep you from returning the thing if anything goes wrong with in it's 3 year warrenty.
Anyhow: Try this with your current router, If you are running it protected, turn it off and try again. If that does not work, do a test network settings and read EXACTLY what it says. If you don't understand it, post it here, or call microsoft. So far as I've seen, they are nice about helping people (unlike linksys). You may have to either get another brand router, of just LAN the thing like you are now. You can also get help in the forums at www.xbox.com
Dark Transparent said:
Umm... Read the directions? Do you have an obscure router? I dunno.